You will never find that on HD's site as they don't have any building materials.
Go to
www.totem.ca and follow this chain after picking a store: GENERAL DEPARTMENTS > HARDWARE > BUILDERS HARDWARE > STRUCTURAL HARDWARE > POST SUPPORTS
However, I would not do that deck that way unless you want to rebuild it/ fix it/ pay out lawsuits every other year. There's a reason building code says piles 4 feet down; and not because they are "in" with the concrete industry.